Comment 2 for bug 1679366

The error in the logs is:

> Installation finished. No error reported.
> Running in non-interactive mode, doing nothing.
> dpkg: error processing package shim-signed (--configure):
> subprocess installed post-installation script returned error exit status 1

This appears to indicate that your system has dkms modules installed, and therefore must have secureboot administratively disabled in order to ensure your system remains bootable, but because this was a non-interactive upgrade, shim-signed was unable to prompt you about this.

It also appears that the signed kernel package is missing from your system, which would also prevent secureboot from working.

I recommend that you install the linux-signed-image-generic package on your system.

Do you know if you have dkms modules installed on your system? (/var/lib/dkms)